1. Field of the Invention
An improved knit pile fabric, the methods therefor and circular knitting machinery with improved pile elements for manufacturing the improved knit pile fabric.
2. Description of the Prior Art
Knitted pile fabrics are generally composed of ground yarns forming a ground fabric in different constructions to which pile yarns, forming protruding pile loops, are meshed.
In the overwhelming majority of proposals for knitting pile fabrics the knitting of the base or ground fabric and the forming of pile loops is realized simultaneously by knitting the ground yarn and the pile yarn together into stitches cross the complete course.
With exception of the proposal described in the German Patent No. 671 333 thereby exclusively one pile yarn is knitted together with one ground yarn to stitches. If the ground fabric is knitted into plain single jersey courses a pattern is exclusively obtained by selecting the pile elements for pile forming or plating (non-pile forming) or forming pile loops of different length (for example as described in the German Patent No. 656 588, British Patent No. 462.662, U.S. Pat. No. 3,477,255). Colored patterns are produced by feeding different pile yarns to a sequence of succeeding feeders and knitting pile loops in one of the feeders in a predetermined section and meanwhile the other courses in this portion are composed of plated stitches. As a result, the pile density is reduced according to the number of courses knitted in a sequence, so that for a sufficient pile density the sequence of different pile yarns is limited usually to two.
Based on the foregoing described method for pile knitting the number of pile yarns in a complete course is only increaseable by knitting a predetermined number of sectional courses in a sequence of at least two feeders after which the complete course is realized. Such methods are described in the proposals according to the U.S. Pat. Nos. 2,710,527; 4,409,800; German Patents 1 153 482; 1 585 051; in which ground yarn and pile yarn floats will spread over the wales knitted from alternative pile and ground yarn. The manufacturing of patterned pile fabrics according to this proposals is limited by the floats of the ground yarns which will also project from the fabric if they spread over more than three wales whereby they may be cut off in the required shearing operation after knitting to remove the float portions of the pile yarns and making the pattern visible.
To avoid longer floats from the ground yarn when knitting partial sections of a fabric, it is proposed, according to European Patent No. 0 043 135 (corresponding to U.S. Pat. No. 4,633,683) to arrange the ground yarn between the knitting sections in a lay-in (accordion-type) structure. In a further proposal, referenced European Patent No. 0 072 425, the non-knitting, respectively non-pile forming yarns are tied into the ground fabric in a laying structure, so that this fabric is usable after knitting in the looped construction.
Lay-in portions of yarns excluded at least from knitting ground fabric will widen the fabric width and will reduce also the course density and therefore also the pile density and the elasticity of the fabric.
To overcome such limitations a number of proposals over the last fifteen years have been made to knit at least two pile forming yarns into a ground fabric from one ground yarn. To avoid the handicaps of the method referred in the German Patent No. 671 333, resulting from the required exact adjustment of the yarn carrier for feeding a first pile yarn to a first group of needles and arranging thereafter this first pile yarn in the backs of the needles of a second group of needles, whereby an unverifiable tensioning of the first pile yarn (especially according to the provided pile length, yarn friction, alteration of the needles etc.) must be accepted; it is proposed to provide subsequent sections of ground and pile yarn feeders in which at least the pile yarns are sinked or prelooped to sectional pile loop portions which are knit in a final section of a knitting sequence together with a ground yarn to a complete course. Methods for manufacturing this type of fabric are described in the U.S. Pat. Nos. 4,612,784; 4,989,421; 5,167,133; European Patent Publications No. 0 335 618; 0 594 187; 0 629 727; German Patent Publications No. 40 33 735; 41 29 845; 195 05 646.
As referred in these publications the ground yarn will knit exclusively with one of the pile yarns sectionally Predetermined pile areas, so that the pile yarns excluded from pile knitting will spread or float over the pile portions from alternative pile yarns. Therefore it is supposed that these floats are removed by a shearing process subsequent to knitting. Resulting from this exclusively, velour-type fabrics can be produced while an increased shearing loss, according to the number of pile yarns per course, must be accepted.
To reduce the percentage of pile yarns in the fabric, respectively using courser pile yarns without increasing the portion of pile yarns in the fabric, it is provided in some proposals to mesh the pile yarns into the fabric by tucking.
Analogous to the above-mentioned proposals it is proposed, according to the proposal of European Patent Publication No. 0 484 692, to sink or pre-loop on at least two succeeding pile yarn feeders, alternatively, sectional pile loops and clearing these pile loops from the needle latches in the final ground yarn feeder, so that the pile loops are meshed into the ground fabric by tucking. The overspreading pile yarn portions must be also removed by shearing as referred before.
It is noted that pile fabrics incorporating the pile yarns by tucking are also described according to the proposals of U.S. Pat. Nos. 4,043,151; 4,409,800; European Patent Nos. 0 422 917; and British Patent No. 830,219.
To avoid floats from the pile yarns spreading over pile sections from alternative pile yarns it is proposed, in the German Patent Publication No. 27 04 295, to knit two pile yarns in subsequent feeders in alternate wales to a continuous lay-in construction where, in each feeder, predetermined pile elements draw out pile loops. Both pile yarns are meshed to a plain ground course.
With this proposal it is exclusively possible to knit two pile yarns into a course without floats in the pile yarn so that the fabric can be used with the original loop structure or with severed pile loops with a reduced shearing loss. The disadvantage of this proposal is that only two pile yarns can by meshed to a ground fabric when a sufficient pile density will be obtained and the pile yarns are meshed to the base fabric exclusively by tucking, which will reduce the pile density.